Position indicating apparatus



Feb. 24, 1953 R. M. PAGE POSITION INDICATING APPARATUS Filed sept. 19, 1942 2 SHEETS-SHEET l INVENTOR ROBERT M. PAG

ORNEY N .MSL

Feb. 24, 1953 R. M. PAGE 2,629,866

POSITION II\TI.`JJCI5L'I`II\"1 APPARATUS Filed sept. 19, 1942 2 SHEETS-SHEET 2 CATHODE RAY TUBE CENT?? MUMROL rl. ECTION COILS `SWEEP DEFLECTION COILS IAVEATOR ROBFRT lVl PGE Patented Feb. 24, 1953 UNITED STATES PATENT oFElcE POSITION INDICATING APPARATUS Robert M. Page, Washington, D. C. Application September 19, 1.942, Serial No. 469,010

6 Claims. (Cl. 343-11) (Granted under Title 35, U. S. Code (1952),-

sec. 266) This invention relates to radio echo apparatus and more particularly to methods of andmeans for detecting the presence of remote objects included within a neld extending 360 about a reference point and for producing visual plan position indication of such area whereon detected remote objects are indicated in such a manner as to simultaneously Show range and direction thereof.

Radio echo apparatuses disclosed by the prior art include a directional beam antenna from which equally spaced energy pulses are emitted at a constant rate, and an indicator, such as a cathode ray oscillograph, upon which a time sweep is impressed in synchronism with the energy pulses emitted from the antenna. When the emitted energy pulses impinge upon remote objects, echo pulses are reflected from the objects and applied to the indicator in such a manner as to produce an indication on the sweep whichVpor-l trays a measurement of range of the remote object frorn which the echo pulse reected. In the prior system directional indications of remote objects detected in the foregoing manner are derived from the angular position of the directional beam antenna. Directional indications obtained in this manner are not of a high degree of accuracy since the directional energy beam emitted from the antenna must necessarily have substantial widths, approximately equal to an arc of 1D to 15 degrees, and echo pulse indications are therefore produced on the indicator Whenever a remote object is included within any portion of the beam. Consequently, it becomes necessary to continually adjust the antenna bearing until echo pulse indications of maximum amplitude are produced, in which case it is assumed that the middle of the directional energy beam, the portion thereof having the greatest power, is directed toward the object, and also that the antenna is likewise pointing directly toward the object. The latter operations are extremely difficult to perform rapidly with a high degree of accuracy, and the prior systems are therefore only capable of indicating approximate bearings of remote objects.

From the foregoing it can be readily lseen that numerous difculties arise when attempting to determine range and directional indications or" remote objects with a system of conventional construction. As mentioned abovex directional indications, when obtained, are not of a high degree of accuracy, and furthermore, it becomes extremely difficult to obtain a directional indication of a remote object corresponding to a recator for each position of the antenna.

mote object indication produced on the indicator since the means for indicating range and bearing are distinct, isolated devices. Diiiiculties arising because of the latter are more readily comprehended when attempting to determine range and direction of all remote objects included within a ield extending 360 about the apparatus. It is necessary, in the latter instance, to slowly rotate the antenna by extremely small increments throughout 360 and to continually record the echo pulse indications appearing on the indi- When considering the tedious operations required to obtain approximate bearing indications, the fallacies of the foregoing method are obvious, especially in instances wherein the remote objects are moving at high velocities, such as aircraft, for example.

' It is therefore an object of the present invention to provide a novel method for indicating range and direction of remote Objects.

Another object is to provide novel means for indicating range and direction of remote objects.

Another object is to provide novel means for simultaneously indicating range and direction of remote objects on an oscillograph by use of separate coordinates. Y

Another object is to provide a novel radio echo apparatus for producing a plan position indication of remote objects included Within a field extending 360 about the apparatus, with the indication of eachl object simultaneously showing range and direction thereof.

Still another object of the present invention is to provide a novel method for producing a rotating radial sweep of the electron beam of an oscillograph. i

Still another object is to provide novel means for producing a rotating radial sweep of the eleotron beam of an oscillograph.

Still another object is to provide a radio echo apparatus including novel means for producing a radial time sweep ofthe electron beam of an oscillograph and for rotating the sweep in synchronism with rotation of thel antenna of the apparatus whereby range and directional indications of remote objects included within a iield extending 360Aabout the apparatus are simultaneously obtained from the indications produced on the oscillograph. l Y

Still another object is to provide novel electromagnetic means for producing a rotating radial sweep of the electron beam of an oscillograph.

Still another object is to provide a radio echo apparatus having an oscillograph with means for producing a rotating racial sweep oi' the electron beam thereof, including novel means for varying the point about which the sweep rotates.

Other objects and features of the invention will appear more fully hereinafter from. the following detailed description when considered in connection with the accompanying drawings which discloses a radio echo apparatus embodying the principges of the present invention. It 1s to be expressly understood, however, thatv the drawings are designed for purposes of illustration only and not as a definition of the limits of the invention, reference for thev latter purpose being had to the appended claims.

In the drawings, wherein similar reference characters denote similar elements throughout the several views:

Fig. 1 is a diagrammatic illustration, partly in section, of a radio echo apparatus embodying the principles of the present inventiomand j Fig. 2 is a .sectional illustration through line 2-2 of Fig. 1.

It is contemplated by the, present invention to produce. a highly directive beam of energy, such as a series of equally spaced radio frequency pulses, which is continually rotated toscan an area extending 360 about a-reference point with the directive energy, and to produce a radial sweep of the electron beam of anl oscillograph which rotates about a xed point on the oscillograph screen in synchronism. with rotationy of the. directional energy beam. The rate of emission of the directional energy is synchronized with the radial sweep of the electron beam. so that energy reflected from. remote objects in.- cluded in the scanned area produces indications on the sweep, at certain distances fromthe rotating ends thereof, which are direct measurements of range of the remote object. from which the energy reflected,l while the angular positionof` the sweep, at the instant a reflected energy indication is produced thereon, represents the direction of the remote object. Withan apparatus having the foregoing characteristics,I aV visual plan positiony indicationv is produced on the os.- cillograph screen which portrays the remote ob,- jects included within the scanned area at certain radial and angular positionswith respect tothe center of the oscillograph screen in a manner corresponding to the range and direction of remote objects with respect to the apparatus. An` indication of the foregoing type is disclosed and described more fully in the application of H'. G. Busignies, Serial No. 380,982, filed February 28, 1941, for Distance and Direction Indicating System and now Patent 2,468,032.

With reference more particularly to the drawings, the radio echo apparatus constructed innaccordance with the principles of the present invention that is disclosed therein. includes directional beam antenna I, pulse transmitter II and` pulse receiver I2. Transmitter II and receiver I2 are connected to antenna l0 by means of duplexing circuit I3 which automatically functions to form individual connections between the transmitter and the antenna, and between the antenna and the receiver so that a single antenna is employed for transmission as well as reception. The output of transmitter I'I is modulated by electronic keyer I4 in such a manner that the former produces equally spaced energy pulses, such as radio frequency pulses, at a rate determined by synchronizer I5 which controls operation of keyer I4, which are emitted from antenna IU in the form of a directional energy emission. Energy received at the antenna is passed through receiver I2 and coupling condenser I6 to control grid I'I of oscillograph I8, to modulate the intensity of the electron beam of theoscillograph. Antenna l0 is rotated, in a horizontal plane for example, by means of motor I9 through shaft 53, so that the directional eni 1 ergy pulses emitted from the antenna may be scanned over an area extending 360 about the antenna, or through any desired angle. Antenna II). is to bek of any suitable construction capable of producing a highly directive energy emission, and` transmitter II and receiver I2 are designed in sucha-manner as to properly transmit and receive pulse energy, such as transmitters and r.,- ceivers;employedv in conventional television equipment. Oscillograph I8 is of conventional construction in so far asthe same comprises an evacuated cylindrical envelope 20 having a viewing. screen, not shown, at one end, with electron emitting means mounted inthe other end thereof.. The. electron emitting means includes cathode. 2|, heater element 22, grid 23 and anode 24, from. which the electrons are emitted at eX- tremely high velocities toward the viewing screen.

As. mentioned heretofore, it is an object of the present invention to provide novel electromagnetic means associated with oscillograph I8 for continually radially deilecting the electron beam emitted from cathode 2I in synchronism with the pulse energy emitted. from antenna I0 in a directionv corresponding to the direction of the pulsev energy emission fromk the antenna. As shown in the drawing, the foregoing means comprises cylindrical coil supporting member 25 mounted for rotation` about the outer periphery of envelope 20 by means of anti-friction bearings 23 which cooperate with member 25 and race member 21; the latter member being secured to the outer periphery of envelope 20, between the electron beam emitting means and the oscillograph viewing screen, by any suitable means. Deflection coils 28, 28- are carried by member 25 and are electrically connected to slip rings 23 and 30 through conductors 3I- andv 32. The aforementioned means also includes saw-tooth wave generator 33 of conventional design to produce sawtooth varying currents, as well as a source of constant direct current, the purpose of the latter will appear more fully hereinafter. Synchronizer I5 is connected to generator 33 to control operation of the latterV in such a manner that generation of saw-tooth current wave forms are initiated at the instant an energy pulse is generated at transmitter AII. The output of generator 33' is fed to deflection coils 23, 223 through conductors 34 and 35 which respectfully terminate at contacts 36 and 3l slidably mounted on slip ringsZS and 30.

Deflection coils 28, 28 are diametrically mounted in supporting member 25 and are wound in such a manner as to produce a uniform uni-directional electromagnetic i'leld therebetween, that passes through envelope 2t, when a source of direct current is applied thereto. Application of saw-tooth current wave forms to the delection coils produces a uniform electromagnetic iield between the coils, the strength of which varies at a constantly increasing rate, from a Jfield of zero strength, at the originating point of the saw-tooth wave forms, to a i'leld of maximum strength when the saw-tooth wave forms attain maximum current values.' 'The electron beam emitted from cathode 2| normally moves along the central axis of envelope 2D; however, when a saw-tooth varying electromagnetic field is applied between the deiiection coils, the electron beam is deflected, in a direction at right angles to the direction of the electromagnetic field, by an amount directly proportional to the strength of the iield. It is to be expressly understood, therefore, that the electron beam is radially moved from the center of the oscillograph screen upon application of each saw-tooth wave form to the deflection coils. When a series of sawtooth current wave forms are applied to the defiection coils, a constant direct current, the average current value of the sawetooth Wave forms, produces a constant electromagnetic field between the coils. The constant field tends to maintain the electron beam at some position remote from the central axis of envelope 29. Since, as mentioned heretofore, an object of the present invention is to produce a radial sweep of the electron beam, that is, a sweep that originates at the center of the oscillograph screen, a source of direct current is also applied to the deflection coils, by way of conductors 315 and 35, of the proper polarity to produce an electromagnetic i'leld in opposition to the constant iield produced by the aforementioned average direct current. With the foregoing arrangementthe electron beam is radially moved from the center of the osoillograph screen upon application of each saw-tooth current wave form.

In order to rotate the radial sweep of the electron beam in synchronism with rotation of antenna iii in such a manner that the electron beam continually moves in a direction corresponding to the direction of emission of the directional energy from the antenna, means are provided for synchronizing the angular positions of coil supporting member and antenna iii, and for rotating the member and the antenna in such a manner as to continually maintain such synchronous angular relationship. As shown, the foregoing means comprises annular gear 33, secured to the outer periphery of coil supporting member 25 at one end thereof, and pinion 39, rotatably connected to motor |.9 through shaft d0, which cooperates with annular gear 38. The driving connections between motor I9 and antenna iti, and between the motor and coil supporting member 25, are so designed thatv coil supporting member 25 rotates through a complete revolution during the time requiredy to rotate antenna i9 throughout 360, while the coil supporting member is angularly positioned about the oscillograph in such a manner that the electron beam moves in a direction corresponding to the direction of emission of the directional energy from the antenna.

As previously mentioned, means are provided by the present invention for varying the point about which the radial sweep of the electron beam rotates to any desired position within or outside the oscillograph screen. By varying the point about which the radial sweep rotates, and by exp-aladiner the length of the sweep, any desired portion of the area scanned by the directional energy emitted from the antenna may be indicated on the entire area of the oscillograph screen. With an arrangement having the foregoing characteristics, indications of objects, at extreme remote positions with respect to the apparatus, are obtained in such a `manner that range and directional indications thereof are -plied to Ythe coils.

'rapidly obtained with a high degree of accuracy, as will appear more fully hereinafter.

The foregoing means comprises cylindrical coil supporting member 4| rotatably mounted about the outer periphery of member 25 by means of anti-friction bearings 42. Member 4| is rotated upon manual movement of knob i3 which is secured to pinion M, while the latter eiement coopcrates with annular gear @Vi mounted on the outer periphery of member di. Deiiection coils 46, 46 are carried by member 4| in diametric relation, and are wound in such a manner as to produce a uniform uni-directional electromagnetic field between the coils, and through envelope 20, when a source of direct current is apnected to slip rings lil and lig carried by meinber 4|. The output of variable direct current supply 59 is fed to deflection coils |55, i6 through conductors 5i) and 5|, each of which terminate in contacts that cooperate with slip rings 41 and t3. When it is desired to move the point about which the radial sweep of the electron beam rotates, the output of supply 49 is regulated until the direct current fed to coils Il?, Gd produces an electromagnetic field of suiiicient strength to deflect the electron beam of the oscillograph the desired amount from the center of the oscillograph screen. Member 4| is then rotated, upon manual movement of knob d3, to vary the direction that the electron beam is moved until the desired angular position thereof is obtained. In order to expand the radial sweep of the electron beam, the amplitude of the saw-tooth current wave forms from generator 33 is increased upon adjustment of control 52 associated with the generator.

As mentioned heretofore, transmitter produces a series of equally spaced energy pulses, such as radio frequency pulses, upon operation of keyer' lll, at a rate controlled by synchronizer l5, which are emitted from antenna iii in the form of a highly directive energy pulse emission. Synchronizer i5 also controls operation of sawtocth generator 33 in such a manner that generation of a saw-tooth current wave form is initiated at the instant an energy pulse is generated at the transmitter. The saw-tooth varying current output, as well as a source of direct current, from generator 33 is applied to deflection coils 28, 28 to produce a uni-directional sawtooth varying electromagnetic field within envelope 23 which radially deects the electron beam emitted from antenna 25, upon application of each saw-tooth wave form to the coils. Since antenna lil and coil supporting member 25 are synchronously rotated upon operation of motor i9, the electron beam continually radially sweeps in a direction corresponding to the direction that the energy pulses are emitted from the antenna.

When antenna lil is continually rotated to scan an area extending 360 about the antenna with the directional energy emission, the energy pulses impinge upon and reflect from all remote objects included within the scanned area. The reflected energy pulses are received at antenna le, passed through receiver l2 and applied to control grid of oscillograph I8, by way of condenser I5, to modulate the intensity of the electron beam thus producing a visual indication on the oscillcgraph screen. Since lthe electron beam initiates radial movement in a direction corresponding to the direction ofthe pulse energy emission from the antenna, whenever an energy pulse is emitted,

The deection coils are 'conir Y' the electron beam is modulated, response to reception of reflected energy pulses corresponding to the energy pulse emitted at the instant radial movement of the electron beam initiated, when the same occupies a certain radial distance from the center of the oscillograph screen that is a direct measurement of range of the object from which the energy pulse reiiected, while the angular position of the radial sweep at the instant the indicationv is produced thereon indicates the direction, or azimuth angle, oi' such object.

In the event that more accurate range and directional indications of a certain remote object detected in the foregoing manner is desired, the radial sweep of the electron beam is expanded by increasing the amplitude of the saw-tooth current wave forms by adjustment of control 52, and supply 49 is regulated to apply a source of direct current to deflection coils 46, 46 to produce a uni-directional electromagnetic field that deects the electron beam in a direction determined -by the angular position 4of the deflection coils. The angular position of deflection coils 46, 46 is varied, upon rotation of knob 43, to occupy a position wherein the electron beam is deiiected in a direction substantially opposite the direction of the remote object of which an indication. is desired, with respect to the antenna, while the current fed to the deilection coils is regulated in such a. manner as to move the electron beam to a new point of rotation that is suflicient distance in the aforesaid direction from the center of the oscillograph screen so that the expanded radial sweep utilizes the entire diameter of the screen. Since deflection coils 46, 46 are capable of rotation throughout 360 any remote object included within the scanned area may be individually indicated in the foregoing'manner.

There is thus provided by the present invention novel methods of and means for simultaneously indicating ranger and direction, or the azimuth angle, of remote objects on the screen of an oscillograph, or any other suitable indicating device. The novel means disclosed and described herein is so characterized that a visual plan position indication of all remote objects included within an area extending 360 about a reference point is readily obtained, wherein remote, objects are indicated on the viewing screen of an oscillograph at radial and angular positions with respect to the center of the screen that respectively correspond to ranges and azimuth angles of remote objects with respect to the reference point. Furthermore, the present invention provides novel electromagnetic means for producing an extremely stable radial sweep of the electron beam of an oscilligraph and for rotating the sweep in synchronism with rotation of a remote rotatable member with a high degree of accuracy, as well as providing other novel means for varying the point about which the radial sweep rotates to any desired position so that extremely accurate range and directional indications of preselected remote objects maybe readily obtained.

Although several modifi-cations of the present invention have been shown and described in detail herein, it is to be expressly understood that various changes and substitutions may be made therein without departing from the spirit of the invention as well understood by those skilled in the art. Reference therefore will be had to the appended claims as a definition of the limits of the invention.

The invention described herein may be manufactured and used by or for the Government oi 8 thev United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. In an apparatus for indicating range and azimuth of remote objects, means producing a directional pulse energy emission, means rotating said directional pulse energy emission, an oscillograph, a plurality of deilection coils rotatably mounted -on said oscillograph, means applying saw-tooth currents synchronized with said directional pulse emission to said coils for producing a radial sweep of the electron beam of said oscillograph, means rotating said coils in synchronism with rotation of said direction pulse energy emission whereby said sweep rotates in synchronism with rotation of Vsaid directional pulse energy emission, means producing indications on said sweep when said pulse energy impinges upon and are reflected from remote objects whereby range of said remote objects is represented on said sweep by the distance of said indications from onev end thereof, and whereby azimuth of said remote yobjects is present-ed from the angular displacement of said sweep at the instant said indications are produced thereon.

2. In an apparatus' for indicating range and azimuth of remote objects, means producing a directional pulse energy emission, means rotating said'directional pulse emission, an oscillograph, a plurality of deflection coils rotatably mounted on saidl oscillograph, means applying saw-tooth culrents synchronized with said directional pulse emission to said coils for producing a radial sweep of the electron beam of said oscillograph, means applying saw-tooth currents synchronized with said directional pulse emission to said coils for producing a radial sweep of the electron beam of said oscillograph, means rotating said coils in synchronism with rotation of said directional pulse emission whereby said sweep rotates in Synchronism with rotation of said directional pulse emission, means supplying a source of direct current to said coils for rotating said sweep about a xed point, means producing indications on said sweep when said directional pulses'impinge upon and reect from remote objects whereby range of said remote objects is represented on said sweep by the distance of said indications from one end thereof, and whereby azimuth of said remote objects is rep esented from the angular displacement of said sweep when said indications are produced thereon.

3. In an apparatus for indicating range and f azimuth of remote objects, means producing a directional pulse energy emission, means rotating said directional pulse energy emission, an oscillograph, a plurality oi" deflection coils rotatably mounted on said oscillograph, mean-s applying saw-tooth currents synchronized With said directional pulse energy emission to said coils fOl producing a radial sweep of the electron beam of said oscillograph, means rotating said coils in synchronism with rotation of said directional pulse energy emission whereby said sweep rotates in Synchronism with rotation of said directional pulse energy emission, means producing indications on said sweep when sai-d energy pulses impinge uponv and reflect from remote objects whereby range of said remote objects is represented on said sweep by the distan-ce of said indications from one end thereof, whereby azimuth of. said remote objects is represented from the angular displacement of said sweep when said indications are produced thereon, a second set 9 of deflection coils rotatably mounted on said oscillograph, means supplying direct current to said second set, and manually operable means for rotating said second set to vary the position of the point about which said sweep rotates.

4. In an apparatus for indicating range and azimuth of remote objects, means producing a directional pulse energy emission, means rotating said directional pulse energy emission, an oscillograph, a plurality of deflection coils rotatably mounted on said oscillograph, means applying saw-tooth currents synchronized with said directional pulse energy emission to said coils for producing a radial sweep of the electron beam of said oscillograph, means rotating said coils in synchronism with rotation of said directional pulse energy emission whereby said sweep rotates in synchronism with rotation o1' said directional pulse energy emission, means producing indications on said sweep when said energy pulses impinge upon and reflect from remote objects whereby range ci said remote objects is represented on said sweep by the distance of said indications from one end thereof and whereby azimuth of said remote objects is represented from the angular displacement of said sweep at the instant said indications are produced thereon, a second set of deection coils rotatably mounted on said oscillograph, means applying direct current to said second set of coils for displacing the point about which said radial sweep rotates, means Varying said direct current for controlling the degree of displacement of' said point, means varying the amplitude of said saw-tooth currents for expanding the radial movement of said electron beam and means rotating said second set of coils for Varying the angular position of said displaced point.

5. An apparatus for indicating continually rthe position of a remote rotatable member on an oscillograph comprising, constant amplitude magnetic sweep producing means disposed outside of said oscillograph producing a periodic constant amplitude sweep of the electron beam of said oscillograph throughout a radius of said oscillograph having a fixed orientation relative to said means, and means synchronized with said remote rotatable member rotating said magnetic sweep producing means in synchronism with the rotation of said member to rotate said sweep about its center-most end.

6. In an apparatus for indicating range and azimuth of remote objects, means producing a directional pulse energy emission, means rotating said directional energy emission in azimuth, a cathode ray tube indicator, constant amplitude magnetic sweep producing means disposed outside of said cathode ray tube indicator producing a periodic constant amplitude sweep of the electron beam of said indicator throughout a radius JheeOIf having a fixed orientation relative to said magnetic sweep producing means, the initiation of said sweep being synchronized with the emission of energy, means synchronized with said means rotating said directional energy emission for rotating said magnetic sweep producing means in synchronism with the rotation of said directional energy emission, means modulating the electron beam of said cathode ray tube indicator for producing indications on said indicator in response to the receipt of said directional energy emission after reection, whereby range of said remote objects is represented by a radial measurement of the indications on said sweep and whereby azimuth of said remote objects is obtained from the angular position of said sweep at the instant said indications are produced.

ROBERT M. PAGE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,535,329 MacGregor-Morris et al.

Apr. 28, 1925 1,768,262 Marrison June 24, 1930 2,007,380 Morlock July 9, 1935 2,143,035 Smith Jan. 10, 1939 2,151,917 Hyland Mar. 28, 1939 2,189,549 Hershberger Feb. 6, 1940 2,211,614 Bowie Aug. 13, 1940 2,224,933 Schlesinger Dec. 17, 1940 2,231,929 Lyman Feb. 18, 1941 2,241,809 De Forest May 13, 1941 2,263,377 Busignies et al. Nov. 18, 1941 2,313,966 Pooh Mar. 16, 1943 2,400,791 Tolson May 2l, 1946 2,412,631 Rice Dec. 17, 1946 2,468,032 Busignies Apr. 26, 1949 2,541,030 Busignies Feb. 13, 1951 FOREIGN PATENTS Number Country Date 494,263 Great Britain Oct. 24, 1938 108,556 Australia Sept. 14, 1939 864,375 France Apr. 25, 1941 

